What is the main goal of wastewater treatment?

The main goal of wastewater treatment is to reduce biochemical oxygen demand (BOD) to safe levels. BOD measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. High BOD levels indicate a high level of organic material and cause oxygen depletion in receiving water bodies, which can harm aquatic life. By reducing BOD, wastewater treatment processes ensure that the effluent released into the environment is less harmful and can support aquatic ecosystems while meeting regulatory standards for water quality.

While increasing nutrient levels, promoting algae growth, and generating energy from waste can be components or secondary objectives of some treatment processes, they are not the primary goal of wastewater treatment. The primary intent remains the protection of water quality and public health through the reduction of organic pollutants and the control of nutrients to prevent issues such as eutrophication.